The Whatman™ GD/X™ 13 syringe filter is specifically designed for high particulate loaded samples up to 10mL in size. GD/X™ syringe filters are constructed with a pigment-free polypropylene housing containing a pre-filtration stack of Whatman™ GMF 150 (graded density) and GF/F glass microfiber membrane media. The innovative, graded density of the GMF 150 pre-filter medium has a coarse top layer meshed with a fine bottom layer that retains particles to 1.0 µm. The GF/F filter then retains particles down to 0.7 µm. This innovative pre-filter stack is then followed with the primary filtration membrane. Whatman™ GD/X™ filters eliminate sample contamination and allow you to filter even the most difficult samples with less hand pressure. GD/X™ syringe filters can process three to seven times more sample volume than standard syringe filters. The syringe filter construction facilitates exceptional loading capacity with fast flow rates. This prevents the build-up of back pressure typically caused by the blocking of an unprotected membrane. Membrane: PTFE.